2006 Fiscal Year Final Research Report Summary
Analysis of temporal and spatial coupling between cerebral microcirculation and neural activity by optical coherence tomography
| Project/Area Number |
16591467
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Cerebral neurosurgery
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| Research Institution | National Cardiovascular Center Research Institute |
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Principal Investigator |
SEKI Junji Natl Cardiovasc Ctr Res Inst, Dept Biomed Eng, Lab Head, 生体工学部, 室長 (20163082)
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| Co-Investigator(Kenkyū-buntansha) |
TAKAMIZAWA Keiichi Natl Cardiovasc Ctr Res Inst, Dept Biomed Eng, Res Assoc, 生体工学部, 室員 (10163312)
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| Project Period (FY) |
2004 – 2006
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| Keywords | optical coherence tomography / microcirculation / neuro-vascular coupling / reactive hyperemia / cerebral cortex / Doppler OCT / velocity profile / neural plasticity |
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| Research Abstract |
This research project was aimed to analyze temporal and spatial coupling between cerebral microcirculation and neural activity in the cerebral cortex using optical coherence tomography (OCT), which was especially designed for in vivo imaging of biological tissues in our laboratory
Velocity profiles along the vessel diameter in the pial microvessels were measured by OCT. The velocity profiles were parabolic in shape at any time, while the centerline velocity pulsated synchronously with the arterial pressure. They indicate that the blood flow in the pial microvessels is a quasi-steady laminar flow, which is consistent with the theoretical prediction. Following the sensory stimulation, the temporal mean velocity in pial arterioles perfusing the somatosensory cortex increased 13% from the control, while the velocity pulsation increased 40%. Such a significant difference places a restriction on the regulatory mechanism of regional cerebral blood flow.
In order to eliminate the blood relating
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effects on the OCT signal change following stimulation, cortical slices of the rat brain were used for simultaneous measurements of OCT and electrophysiological recordings. The OCT signal changed within 1 sec after the electrical stimulation at the site showing large fEPSP, and the maximal change occurred a few seconds after the stimulus. The changes in OCT signal presumably indicate increase in reflectance of the cortical tissue. The possible mechanisms of the increased reflectance include swelling of neuronal cells.
To study neural plasticity by OCT, we chose SI and MI cortices of mice under the influence of sciatic nerve chronic constriction injury which is a model of neuropathy. OCT images revealed that the scattering intensity within the hindlimb area of SI and MI regions was higher in the hemisphere contralateral to the ligation than in the ipsilateral hemisphere. Our data suggest that the neuropathic pain gives rise to the neural plasticity within the hindlimb area of SI and MI contralateral to the ligated nerve. Less
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